thompster Posted July 1, 2017 Share Posted July 1, 2017 Just taken the engine out to investigate my edal vibration to find the clutch plate has disintegrated. The flywheel side of the plate is perfect, the pressure plate side is barely worn but half the plate has shredded. The rivets are still intact. Photo below. The AP cover looks fine. The vibration started on a long motorway run back from Le Mans. What's the likely cause so I can avoid it happening again? Link to comment Share on other sites More sharing options...
Graham King Posted July 1, 2017 Share Posted July 1, 2017 Thompster, mine did exactly the same on a track day at Brands, whether all the damage was done there I'll never know. My best hypothesis as to why it happened was several high speed missed gear changes that resulted in the clutch being engaged under power at high rpm that put too much torque through it. Does your car have a lot of power/torque?Graham Link to comment Share on other sites More sharing options...
elie boone Posted July 1, 2017 Share Posted July 1, 2017 Most probably cause is that the plate overheated, could be by having your foot on the clutch pedal or used to much engine braking. Link to comment Share on other sites More sharing options...
thompster Posted July 1, 2017 Author Share Posted July 1, 2017 No sign of any overheating of the plate but that's not to say it hasn't at some point. I'm not a clutch rider either though the previous owner may have been - in 25 year driving this is the first clutch I've had to do. My car is a lowly 140bhp on a good day with 12k miles (10k of those it was 120bhp). I have been known to make the occasional heavy downshift though.Having done some reading there are quite a few reports of the AP plate shedding its material on one side. My knackered plate is manufactured by Schwungrad whereas the latest AP plates are made by Valeo. I might give them a ring on Monday and see what they say but at the minute I'm pondering alternatives. Link to comment Share on other sites More sharing options...
Wrightpayne Posted July 1, 2017 Share Posted July 1, 2017 I had a standard one let go in similar fashion @ 6 years old / 7k miles. Used the opportunity to upgrade to AP and been fine since.Ian Link to comment Share on other sites More sharing options...
elie boone Posted July 2, 2017 Share Posted July 2, 2017 If you do heavy downshifts go to a paddle clutch with a spring center that will withstand heavy downshifts no problem. Link to comment Share on other sites More sharing options...
John Vine Posted July 2, 2017 Share Posted July 2, 2017 I suffered the same problem a couple of years ago, except that my driven plate shed the friction material on the flywheel side -- full saga here.I returned the plate and cover to AP for their opinion. The actual cause of the failure was (and remains) something of a mystery, but possible causes included: Excessive heat due to clutch slip Excessive revs Shock to the retaining rivets caused by running clutchless for 100 miles plus starting the car in gear whenever forced to stop (as a result of seal failure in the master cylinder)AP provided a brilliant service, and refurbished the cover and driven plate (which they uprated from 8000 to 9000 rpm) entirely FOC.I suggest you contact AP Racing on roadtech AT apracing DOT co DOT uk. I dealt with a very helpful engineer called Pete Collen. If you end up contacting him, feel free to quote my case (returns ref E5328.10).JV Link to comment Share on other sites More sharing options...
Area Representative Richard Price Posted July 2, 2017 Area Representative Share Posted July 2, 2017 I've known a couple of friction plates to break up, both of which failed in similar circumstances, where the car was slowing from high speed in a high gear, and a lower gear was selected , but the clutch not engaged. Therefore, the driven wheels drive the gearbox and when the low ratio is selected, the friction plate can be spun up to significantly higher revs than it will ever experience when being driven by the engine. Link to comment Share on other sites More sharing options...
thompster Posted July 5, 2017 Author Share Posted July 5, 2017 Thanks all. I contacted AP with a photo but they said as its OEM I'd have to go through Caterham who then might send it to AP for inspection. Not very helpful but rules is rules. I've ended up ordering a Helix replacement - unfortunately from Burton Power who it transpires are hopeless and rude. Live and learn... Link to comment Share on other sites More sharing options...
Englishmaninwales Posted July 5, 2017 Share Posted July 5, 2017 +1 about Burton Power. In fact, worse than hopeless and rude. (If that's possible). Link to comment Share on other sites More sharing options...
John Vine Posted July 5, 2017 Share Posted July 5, 2017 they said as its OEM I'd have to go through CaterhamAh, I should have explained that I contacted CC first (Tony in Parts). He asked me to contact AP direct, but to let him know what AP said.JV Link to comment Share on other sites More sharing options...
John Vine Posted April 21, 2018 Share Posted April 21, 2018 Did you ever establish the cause? What did AP say?JV Link to comment Share on other sites More sharing options...
thompster Posted April 21, 2018 Author Share Posted April 21, 2018 Hi john, after AP had I should go through caterham I didn't bother. I suspect it was downshifts without rev matching property - i try to heel and toe all the time now. My helix one has been fine so far and I'm still not convinced that either the helix or AP plates are anything special though given one is branded valeo and the other as LUK... Link to comment Share on other sites More sharing options...
John Vine Posted April 21, 2018 Share Posted April 21, 2018 Thanks for the update.JV Link to comment Share on other sites More sharing options...
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